This chapter deals with the socio-economic impact of urban agriculture on income generation, poverty alleviation, urban food supply, livelihoods, as well as indirect costs and benefits for society including environmental externalities. Two levels of analysis are considered to assess this impact: the household and the city. The assessment of social and economic impact at the city level suffers more from lack of data than is the case at the household level. A main question is whether urban agriculture should be seen as an informal, residual, subsistence activity or as one that can shift from simple to enlarged reproduction of urban food, by making the best of its proximity to urban consumers and sustaining incomes in the long run.